US2086117A

US2086117A - Coating casting machine

Info

Publication number: US2086117A
Application number: US55947A
Authority: US
Inventors: Lynn B Case
Original assignee: JOHN WALDRON CORP
Current assignee: JOHN WALDRON Corp
Priority date: 1935-12-24
Filing date: 1935-12-24
Publication date: 1937-07-06
Anticipated expiration: 1954-07-06

Description

July 6, 1937. L. B CASE I 2,086,117

COATING CASTING MACHINE Filed-Dec. '24, 1955 2 Sheets-Shet 1 ATTORNEY July '6, 1937. L. 5, CASE 2,086,1'1 7 COATING CASTING MACHINE Filed Dec. 24, 1955 2 Sheets-Sheet 2 I INVENTOR ,3; I ATTORNEY Patented July 6, 1937- UNETED STATES PATENT OFFICE COATING CASTING MACHINE Application December 24, 1935, Serial No. 55,947

10 Claims.

This invention relates to-coating machines and more particularly to machines for casting a coating compound blended with high, medium or low boiling solvents such as varnishes, lacquers and the like onto base materials such as textiles, paper, metals, acetates and regenerated cellulose. Aqueous mixtures may, however be used with the construction shown.

In the casting of a coating on a quick evaporating solvents are used certain difliculties arise. Due to the quick evaporation of the solvents the coatings become so tacky that the casting is extremely difficult to do. If it is necessary to stop the machine the lacquer forms a tacky ridge on the roll which must be removed before coating can be resumed. Solvents must be added to take care of the evaporation and this addition of solvents varies the density of the coating preventing a uniform depth of coating throughout the web. This invention is particularly adapted to casting a coating with quick evaporating solvents but can be used for other coatings.

One of the objects of this invention is to maintain a high saturation point of volatile sola vents in the air surrounding the coating rolls to prevent drying of the lacquer.

Another object of the invention is'to provide a coating machine wherein the movement of the paper may be stopped without stopping the rotation of the coating rolls.

A further object of the invention is to provide means to vary the width of application of lacquer.

on the web of paper. 7 3 Still another object of the invention is to provide accurate adjustments between the rolls.

Referring to the drawings:

Figure 1 is a view in side elevation of a device embodying the principles of my invention as applied to a coating machine.

Figure 2 is a view in side elevation with parts broken off.

Figure 3 is a diagrammatic detail viewshowing the drive of the coating and backing roll.- 4 Figure 4 is a diagrammatic view of a modified form of device.

In carrying out my invention, I cover a predetermined portion of a finished roll face to an even thickness and smoothness and then cast the 50 coating so formed onto the base materials. In so doing, the relative surface speeds of the rolls depend upon the body or fluidity of the coating materials.

In my method and apparatus the coating after 55 being laid on the roll is flowed or transferred onto base where (Cl. 91-49) I the base materialewithout any pressure being exerted on the coating material in the transfer operation from the roll tothe base material. This transfer operation I define as casting the coating onto thematerial.

I provide the usual web of paper I from unwind roll 2 which passes around the usual rubber backing roll 3. .Roll 3 holds the web of paper I against the reverse transfer roll 4 on shaft 5. Reverse turning doctor roll 6 is on shaft I and is cleaned by doctor -8 in the usual manner. Beneath the reverse transfer roll 4 is a movable pan 9 which projects in beyond the center of ,roll,

4 to collect any drip should the coatingrolls be stopped and the lacquer run back from the dam between the rolls. Gates III are fitted to the rolls and hold back the lacquer from the edge of the rolls. It thus permits coating inside of the edge of the web when this is desired. The two gates III are free to slide so that the distance therebetween may be varied. The doctor 8 is slightly above the gates I 0 and a second doctor I I is below the gates and at the bottom thereof. Between the gates III is a scraper III engaging the roller 6 and conoperating with the gates III and doctor I I to confine lacquer scraped off roller 6. Doctor II is heavy and is fixed between the side frames of the coating head and does not fit tightly against roll 4 but is positioned sufficiently near thereto so that if excess lacquer should be pumped into the nip it holds the lacquer up while the machine is running and prevents it running back down the face of doctor roll 4. Doctor II is a tight spring.

doctor and cleans roll 4 and is positioned below doctor II. Thus the two gates I0 slide above doctor II on the face of doctor II and fit between rolls 4 and 6. Rolls 4 and 6 are pivoted at fulcrum I2, the whole head swinging about fulcrum I2 with a support at the lower end by block I3 resting on eccentric I4. Worm I5 controls eccentric I4 through segment gearI6 which is directly connectedto the eccentric. The eccentric I4 has a handle I I and a lock I8. The adjustment therefore between roll 3 and roll 4 is controlled by the micrometer adjustment I5, I6, and if a quick release is desired, the lock I8 is released and the handle pulled out raising roll 4 about one-quarter of an inch above roll 3 through eccentric I4. The movement of roll 4 stops all coating on the paper. The important element is that the coating rolls are still rotating. If it is desired to stop the paper this may be done by releasing clutch I9 which disengages the drive to roll 3 but continues the drive to rolls 4 and 6 to prevent the drying up of the coating rolls.

air into the pool.

The drive is as follows:

The main drive from the motor (not shown) goes to pulley 20 which drives shaft 2| through gear reducer 22 through coupling 23 to variable speed unit 24. The variable speed unit 24 drives through sprocket 25, chain 26, sprocket 21, shaft 5, to coating roll 4. Shaft in turn through

gears

28, 29, drives doctor roll 6 through shaft 1. Gear reducer 22 through clutch l9 and shaft 30 drives sprocket 3|, chain 32, and sprocket 33 on shaft 34 of roll 3. Thus it will be seen that I by throwing out clutch. l9 roll 3 is stopped which in turn stops the feed of the paper without stop-.

ping the coating rolls permitting them to run without drying on the surface. The lacquer is pumped or allowed to flow by gravity into the nip between rolls 4 and 6 through pipe 40 at the approximate rate that it is being used up. Any excess lacquer overflows to the outside container from pan 9.

I have found that one of the difficulties in connection with roll coating, that is, the entrapment of air in the presence of coating can be practically removed in connection with my invention. Where a relatively deep pool of coating material is maintained at the nip, frothing frequently occurs causing the entrapment of air due to the agitation created by the rotation of the rolls. A further cause for the entrapment of air is the emission of the coating into the pool directly from the source of supply. Where a pipe is used for the conduction of liquid with a free stream of the material to the pool, further entrapment occurs by the stream carrying the The apparatus herein disclosed shows the delivery of the coating material in quantities equivalent, to the amount used for the coating thereby maintaining only a very small amount of coating at the nip of the rolls and asthis coating is freshly supplied as it is used the opportunity for the entrapment of air by the agitation of this coating by the rolls is eliminated. In addition, the coating is introduced through the bottom plate or apron of doctor H and allowed to run down the surface thereof thereby permitting any air in the coating to escape before it enters into the nip and also permits the coating to spread uniformly across the plate thereby feeding it throughout the entire length of the nip. In this way, much smaller quantities of coating can be used than where the coating is introduced directly into the stream. An accurate adjustment between rolls 4 and 6 is obtained by a sliding wedge 36 between the supporting bearings of shafts 5 and l. The unique movable head adapts itself to a complete enclosure as shown in Figures 1 and 2 wherein the frame 31 houses most of the head with a face plate 38 secured to frame 31 to close the front. Plate 38 is hinged at 39 to permit inspection and enable the operator to get at the rolls and doctors and make the adjustment with respect to the gates. By the complete enclosure of the coating head a proper saturated atmosphere of solid volatiles can be maintained thereby preventing the drying up of the coating. This complete enclosure is most desirable and cannot ordinarily be done with the usual roll coating machine s.

In the modified form shown in Figure 4, the only difference lies in the enclosing of the head. In this form the doctors 8 and Il operating between the rolls 6 and 4 cooperate with the gates l0, and a cover 38 extending from the top of H to beyond the top of 8 enclose the fountain leaving only a. portion of roll 4 exposed which portion is practically clean of lacquer after contacting the paper on roll 3. However, with this modification, the continuous rotation of the'coating rolls is essential.

It will thus be seen that in this machine accurate adjustment of coating rolls may be effected, a quick release of the coating head may be had with stoppage of the movement of the ing may behad and the necessity of adding solvents is largely dispensed with. 1

What I claim is: 1. In a roll coating machine, a roll for motivating a web of material passed a coating roll,

a coating head including said coating roll, said head pivotally connected to said roll coating machine, means for rotating said coating roll independently of said roll for motivating the web whereby said coating roll may be continuously rotated regardless of the cessation of rotation of the roll for motivating the web.

2.,In a roll coating machine a backing roll, a coating head including a coating roll, said head pivotally connected to said roll coating machine, means for rotating said coating roll regardless of the position of the head and coating roll and independently of said backing roll whereby said coating roll may be continuously rotated during the rotation of the backing roll and during the.

cessation from rotation of the backing roll.

3. In a roll coating machine for lacquer coating and the like, a backing roll, a coating head including a coating roll, means for maintaining an atmosphere saturated with volatile solvents about said coating roll within said head, means for rotating said coating roll independently of the rotation of said backing roll whereby said coating roll is continuously rotated regardless of the rotation of the backing roll.

4. In a roll coating machine for lacquer coating and the like, a coatinghead including a coating roll, said coating head movable as a unit toward and from the material being coated, means for maintaining an atmosphere saturated with volatile solvents about said coating roll 'at all times, means for continuously rotating the coating roll, means for independently motivating the web and stopping same without affecting the rotation of the coating roll. 5. In a roll coating machine, a backing and feeding roll for the material being coated, means for operating said backing and feeding roll, a coating roll, means for continuously rotating said coating roll reversely to the travel of the material being coated and independent of stoppage of said backing and feeding roll, a doctor roll rotating in the same direction as the coating roll, and means for maintaining an atmosphere saturated with solvents about the rolls at the point of application of the coating to the material.

6. In a roll coating machine, a backing and feeding roll for-the material being coated, a coating roll rotating in the reverse direction at the point of contact to the travel of the material being coated, a doctor roll cooperating with the heavy fiat doctor at a predetermined distance from the coating roll and cooperating therewith ,to hold color in the nip between the coating and doctor rolls, and a second fiat doctor for cleaning the coating roll.

7. In a roll coating machine, a backing and feed roll for the material being coated, means for operating said backing and feeding roll, a coating roll, means for continuously rotating said coating roll reversely to the direction of travel of the material and independent of stop-page of said backing and feeding roll, means for varying the speed of rotation of the coating roll, a doctor roll cooperating with the coating roll, said coating and doctor roll being enclosed to maintain a saturated atmosphere of coating solvents about the rolls.

8. In a reverse turning roll coating machine,

a reverse turning coating roll, a doctor roll there-' for, auxiliary doctors forsaid coating roll and said doctor roll, gates and covers cooperating with said-doctors to enclose the nip to maintain an atmosphere saturated with volatile solvents for the coating.

9. In a reverse turning roll coating machine, a reverse turning coating roll, a doctor roll therefor, auxiliary doctors for said coating roll and said doctor roll, gates and covers cooperating with said doctors to enclose the nip to maintain an atmosphere saturated with volatile solvents for the coating, and a variable speed drive for [said rolls.

10. In a roll coater, a coating roll, means for covering a predetermined portion of said coating roll face with fluid material to an even thickness and smoothness, an enclosure for said coating roll, means for liberating entrapped air from 'said material prior to covering said predetermined portion, means for casting said coating without any pre'ssurebeing used on the coating material from the roll to a base material, means for continuously rotating said coating roll independent of stoppage of said .base material and means for controlling the surface speed of the coating roll in accordance with the fluidity of the coating material.

LYNN is. cAsE.